Games
Mac Chess Explorer
http://www.hiarcs.com/mac-chess-explorer.htm
Stockfish 2
https://stockfishchess.org/mac/
MacChess
Sigma Chess
Chess Software Programs for the Mac
http://www.chesscentral.com/chess_software_mac_apple_s/32.htm
Shredder Computer Chess
http://www.shredderchess.com/chess-software/macintosh.html
For iPad and iPhone
running IOS
Chess Knight Free
http://itunes.apple.com/us/app/chess-knight-free/id409228592?mt=12
Chess - Play & Learn
http://itunes.apple.com/us/app/chess-play-learn/id329218549?mt=8